FIELD OF THE INVENTION
The invention relates to an apparatus for catalytically decontaminating or detoxifying exhaust gases, particularly for motor vehicle engines, having a metal carrier body including a plurality of layers of corrugated, or smooth and corrugated, sheet metal, and a jacket that encompasses the metal carrier body and is connected to it by welding techniques.
It is known from German Published, Non-Prosecuted Application DE-OS 27 20 322 to weld metal foils of a metal catalytic converter with electron beams. The individual layers of sheet metal are welded together in such a way that the metal catalytic converter is joined to make an intrinsically rigid insert. The insert is secured in a housing, for instance once again by electron beam welding.
It is known from German Published, Non-Prosecuted Application DE-OS 27 27 967 (which is a continuation of German Published, Non-Prosecuted Application DE-OS 27 20 322) to produce the metal catalytic converter by means of laser welding.
It is known from Published European Application No. 0 245 737 A1, corresponding to U.S. Pat. Nos. 4,803,189; 4,832,998; 4,923,109; and 4,946,822, to form honeycomb bodies of corrugated and smooth sheet metal layers in such a way that the corrugated sheets have straight sections on their ends which extend approximately centrally between the adjoining smooth sheets. The ends of the corrugated sheets must not touch the ends of the smooth sheets and they each rest individually on an encompassing jacket or casing tube, with which they are joined by joining techniques.
A disadvantage of the above-mentioned structures is that very thin metal foils (0.05 mm, for instance) are joined, particularly welded, to a housing that is multiple times thicker. In order to achieve a durable connection between the metal catalytic converter and the housing, the welding depth of an electron or laser beam must be adjusted very precisely, because otherwise the welded connection between the housing and the metal catalytic converter becomes unstable, or else the outer foil layer of the metal catalytic converter will be cut apart.